This invention relates generally to apparatus for housing an array of rechargeable batteries and, more particularly, to apparatus for cooling the batteries while they are being recharged or discharged.
Arrays of rechargeable batteries are enjoying increased use as sources of electrical power for a variety of devices, such as electric vehicles. Such arrays typically include a large number of separate batteries, connected together in series to provide voltages in the range of 100 to 400 volts. In the case of an electric vehicle, it is desirable to locate the batteries in a row within an elongated, tubular housing or tunnel extending centrally along the vehicle's length.
One commonly used battery is the lead-acid battery. During recharging, lead-acid batteries can generate substantial heat, which must be dissipated to prevent the batteries from being damaged. Other batteries, such as nickel-zinc batteries, generate heat during discharge, which likewise must be dissipated to prevent damage.
One technique for dissipating this heat is to size the battery housing to be slightly wider than the batteries array, so as to define a uniform air gap between the housing and the batteries, and to blow air through that air gap, from the housing's forward end to its rearward end. The housing's forward end is preferably located at the forward end of the vehicle. One disadvantage inherent in this means for cooling the batteries is that the batteries located near the housing's forward end are cooled to a substantially greater degree than are the batteries located near the housing's rearward end, due to the heating of the cooling air as it moves past the batteries. This is undesirable, because the ability of many batteries (e.g., lead-acid batteries) to accept a charge varies with temperature, and a temperature variation among the separate cells of the batteries therefore means that some cells will charge more rapidly than others. If the batteries are not uniformly charged, then some of them will discharge before others, leading to the possibility that those batteries will be excessively discharged, and thereby damaged.
It should therefore be appreciated that there is a need for an inexpensive cooling system that is adapted to maintain an array of rechargeable batteries at a more uniform temperature during discharging or recharging. The present invention fulfills this need.